Ultimaker and the ultimate tutorial for it
In order to print via the Octopie interface, the G-code for your 3D models has to be generated with a special Printer profile in Cura. You can download the profile here (Soubor:ultimaker2 plus octoprint.def.zip). To install it, just unzip the downloaded zip file to "C:\Program Files\Cura 2.3\resources\definitions". Then you can generate the G-code for octopi interface with printer profile named "Ultimaker 2+ Octoprint".
Timalapse (independent of octopi)
To star timelapse, login to raspberry pi as "pi" user via SSH and run the following commands:
> screen > ~/timelapse_picamera.py
The "screen" command opens a new bash which does not close after you log out of the SSH, in contrast to normal bash. The next command starts the timelapse script which takes a picture every 30 seconds and stores it in directory /home/pi/timelapse. Please note that the picture is captured by the raspberry pi camera module and not by a USB camera connected to the raspbery pi. As the timelapse script is running you can log out of the SSH. Press Ctrl+A followed by pressing D (this logs you out of the screen) and type exit (this logs you out of the SSH).
As the timelapse runs as long as there is space on the raspberry pi, it has to be stopped at some point. To stop it, log to raspberry pi via SSH and connect back to the bash in screen:
> screen -r
Now, just kill the timelapse script by Ctrl+C.
The captured images are easily accesible via SFTP (for instance, use WinSCP).